PDF Link Handling

To enable links in PDF file, you should set PdfViewerParams.linkHandlerParams.

The following fragment handles user's tap on link:

linkHandlerParams: PdfLinkHandlerParams(
  onLinkTap: (link) {
    // handle URL or Dest
    if (link.url != null) {
      // FIXME: Don't open the link without prompting user to do so or validating the link destination
      launchUrl(link.url!);
    } else if (link.dest != null) {
      controller.goToDest(link.dest);
    }
  },
),

Security Considerations on Link Navigation

It's too dangerous to open link URL without prompting user to do so/validating it.

The following fragment is an example code to prompt user to open the URL:

Future<bool> shouldOpenUrl(BuildContext context, Uri url) async {
  final result = await showDialog<bool?>(
    context: context,
    barrierDismissible: false,
    builder: (context) {
      return AlertDialog(
        title: const Text('Navigate to URL?'),
        content: SelectionArea(
          child: Text.rich(
            TextSpan(
              children: [
                const TextSpan(
                    text:
                        'Do you want to navigate to the following location?\n'),
                TextSpan(
                  text: url.toString(),
                  style: const TextStyle(color: Colors.blue),
                ),
              ],
            ),
          ),
        ),
        actions: [
          TextButton(
            onPressed: () => Navigator.of(context).pop(false),
            child: const Text('Cancel'),
          ),
          TextButton(
            onPressed: () => Navigator.of(context).pop(true),
            child: const Text('Go'),
          ),
        ],
      );
    },
  );
  return result ?? false;
}

PDF Destinations

For PDF destinations, you can use PdfViewerController.goToDest to go to the destination. Or you can use PdfViewerController.calcMatrixForDest to get the matrix for it.

Link Appearance

For link appearance, you can change its color using PdfLinkHandlerParams.linkColor.

For more further customization, you can use PdfLinkHandlerParams.customPainter:

customPainter: (canvas, pageRect, page, links) {
  final paint = Paint()
    ..color = Colors.red.withOpacity(0.2)
    ..style = PaintingStyle.fill;
  for (final link in links) {
    // you can customize here to make your own link appearance
    final rect = link.rect.toRectInPageRect(page: page, pageRect: pageRect);
    canvas.drawRect(rect, paint);
  }
}